1. Field of the Invention
The present invention relates to an interlock mechanism associated with a shift mechanism for a change-speed gearing in a power transmission of an automotive vehicle.
2. Discussion of the Prior Art
In Japanese Utility Model Publication No. 56-26126 there has been proposed an interlock mechanism associated with a shift mechanism for a change-speed gearing in a power transmission of an automotive vehicle, wherein the shift mechanism includes a plurality of fork shafts arranged in parallel with each other and axially slidably supported from a casing of the power transmission to be selectively shiftable toward forward speed-ratio and reverse ratio positions, and wherein the interlock mechanism includes a single interlock plate movably assembled with an end wall of the casing in such a manner as to be selectively engaged with respective annular grooves formed on the fork shafts for permitting axial movement of one of the fork shafts and restricting axial movement of the other fork shafts.
In the interlock mechanism, the interlock plate is formed with a plurality of lock holes to be engaged with the fork shafts extending therethrough and is movable in a plane perpendicular to each axis of the fork shafts. The lock holes of the interlock plate are, however, formed in surrounding relationship with the fork shafts and arranged eccentrically to one another at their centers to permit axial movement of one of the fork shafts when engaged with the other fork shafts. Thus, the interlock plate is moved in various directions, resulting in unexpected troubles in shifting operation of the fork shafts.